[parisc-linux-cvs] linux-2.6 carlos

[Carlos O'Donell]

On Tue, Aug 17, 2004 at 12:43:35PM -0600, Carlos O'Donell wrote:
> CVSROOT:	/var/cvs
> Module name:	linux-2.6
> Changes by:	carlos	04/08/17 12:43:35
> 
> Modified files:
> 	arch/parisc/kernel: entry.S pacache.S real2.S 
> 
> Log message:
> Add comments to all the uses of relied upon translations. 
> Add comments to the code that unconditionally turns on the I-bit. 
> This change is only comments.

Just comments taht I think are in order for others who might look at
this code and wonder.

Index: arch/parisc/kernel/entry.S
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/kernel/entry.S,v
retrieving revision 1.18
diff -u -p -r1.18 entry.S
--- arch/parisc/kernel/entry.S	30 Jul 2004 23:23:20 -0000	1.18
+++ arch/parisc/kernel/entry.S	17 Aug 2004 18:37:59 -0000
@@ -939,6 +939,7 @@ syscall_exit_rfi:
 	STREG   %r19,PT_SR7(%r16)
 
 intr_return:
+	/* NOTE: Need to enable interrupts incase we schedule. */
 	ssm     PSW_SM_I, %r0
 
 	/* Check for software interrupts */
@@ -982,6 +983,8 @@ intr_restore:
 	ldo             PT_FR31(%r29),%r1
 	rest_fp         %r1
 	rest_general    %r29
+
+	/* Create a "relied upon translation" PA 2.0 ref. pg427 */
 	ssm		0,%r0
 	nop
 	nop
@@ -2082,11 +2085,13 @@ syscall_restore:
 	LDREG	TASK_PT_GR29(%r1),%r29
 	LDREG	TASK_PT_GR31(%r1),%r31	   /* restore syscall rp */
 
+	/* NOTE: We use rsm/ssm pair to make this operation atomic */
 	rsm     PSW_SM_I, %r0
 	LDREG   TASK_PT_GR30(%r1),%r30             /* restore user sp */
 	mfsp	%sr3,%r1			   /* Get users space id */
 	mtsp    %r1,%sr7                           /* Restore sr7 */
 	ssm     PSW_SM_I, %r0
+
 	mtsp	%r1,%sr4			   /* Restore sr4 */
 	mtsp	%r1,%sr5			   /* Restore sr5 */
 	mtsp	%r1,%sr6			   /* Restore sr6 */
@@ -2174,6 +2179,9 @@ pt_regs_ok:
 syscall_do_softirq:
 	bl      do_softirq,%r2
 	nop
+	/* NOTE: We enable I-bit incase we schedule later,
+	 * and we might be going back to userspace if we were
+	 * traced. */
 	b       syscall_check_resched
 	ssm     PSW_SM_I, %r0  /* do_softirq returns with I bit off */
 
Index: arch/parisc/kernel/pacache.S
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/kernel/pacache.S,v
retrieving revision 1.6
diff -u -p -r1.6 pacache.S
--- arch/parisc/kernel/pacache.S	25 Apr 2004 14:50:51 -0000	1.6
+++ arch/parisc/kernel/pacache.S	17 Aug 2004 18:37:59 -0000
@@ -68,7 +68,7 @@ flush_tlb_all_local:
 	 * consolidated.
 	 */
 
-	rsm     PSW_SM_I,%r19      /* relied upon translation! */
+	rsm     PSW_SM_I,%r19      /* relied upon translation! PA 2.0 pg427 */
 	nop
 	nop
 	nop
Index: arch/parisc/kernel/real2.S
===================================================================
RCS file: /var/cvs/linux-2.6/arch/parisc/kernel/real2.S,v
retrieving revision 1.14
diff -u -p -r1.14 real2.S
--- arch/parisc/kernel/real2.S	9 Aug 2004 03:01:41 -0000	1.14
+++ arch/parisc/kernel/real2.S	17 Aug 2004 18:37:59 -0000
@@ -149,7 +149,7 @@ restore_control_regs:
 rfi_virt2real:
 	/* switch to real mode... */
 	ssm		0,0		/* See "relied upon translation" */
-	nop				/* comment in interruption.S */
+	nop				/* PA 2.0 ref pg427 */
 	nop
 	nop
 	nop
@@ -186,7 +186,7 @@ rfi_v2r_1:
 	.align 128
 rfi_real2virt:
 	ssm		0,0		/* See "relied upon translation" */
-	nop				/* comment in interruption.S */
+	nop				/* PA 2.0 ref pg427 */
 	nop
 	nop
 	nop